One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(5,6,12,18)(7,13,23,41)(8,24,29,61)(9,30,32,16)(10,15,34,48)(11,35,31,17)(14,42,46,26)(19,52,55,67)(20,47,56,39)(21,38,58,49)(22,51,36,40)(25,59,57,68)(27,45,33,60)(28,50,63,44)(37,64,65,53)(43,54,66,62)(1,2,4,3)(5,7,12,23)(6,13,18,41)(8,25,29,57)(9,21,32,58)(10,20,34,56)(11,36,31,22)(14,43,46,66)(15,47,48,39)(16,49,30,38)(17,51,35,40)(19,33,55,27)(24,59,61,68)(26,62,42,54)(28,64,63,53)(37,50,65,44)(45,52,60,67)(5,8,10,33,11,28,32,42,12,29,34,27,31,63,9,26)(6,14,30,44,17,45,48,61,18,46,16,50,35,60,15,24)(7,19,21,57,22,54,56,64,23,55,58,25,36,62,20,53)(13,37,47,43,40,59,49,67,41,65,39,66,51,68,38,52)(1,3,4,2)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.